This calculator calculates the factor for a slope online.

In construction, the slope factor can be used to easily calculate the area of a roof. The slope factor works with metric and imperial measurements.

Roof area in square metres = length in metres * width in metres* slope factor
Roof area in square feet = length in feet * width in feet * slope factor

Example Calculation:

Roof pitch = 6/12
Roof length including overhangs = 40'
Gable wall length including overhangs = 24'
Enter 6 into the calculator = slope factor = 1.1180
Multiply the roof length by the gable wall length = 40 * 24 = 960
Multiply this amount by the slope factor = 960 * 1.1180 = 1073.28
The area of this roof = 1073.3 sq. feet
The area of a Hip roof equals the area of a gable roof with the same dimensions.